1. Field of Invention
The Dual Control Stem Valve disclosed herein relates to hand valves, and consists in the unconventional construction of the valve, and its distinct operation, and further, in the novel arrangement and combination of its parts, as more fully hereinafter set forth.
It is commonly known by many if not most people knowledgeable in the art that hand operated stem valves may be generally characterized as having either a coarse operating action, that is fast in initiating and terminating flow, which is usually rather difficult to adjust to a more precise desired rate of flow, or a fine gradual operating action, that is difficult by which to rapidly initiate or terminate flow, but which is well suited for metering a more precise specific desired rate of flow. As may be commonly experienced during operation, once ongoing flow has been terminated, varying degrees of difficulty are usually encountered in reinstating a similar desired rate of flow to that having been previously instituted during operation, as may be immediately necessary for a particular operation, when flow is resumed.
Therefore, it is the intent of the present invention to provide a stem valve combining the more desirable previously mentioned operating characteristics of enabling rapid initiation or termination of flow, in combination with more precise metering capability of the rate of flow, and also enable a previously desired rate of flow may be similarly immediately reinstatable upon resumption, to eliminate or substantially reduce the difficulty normally experienced in reobtaining a similar desired rate of flow as may be immediately necessary, when ongoing flow has ben terminated and is then resumed, the principals of which becoming increasingly apparent as they are more fully disclosed in the following specification.
2. Description of Prior Art
Heretofore, a variety of hand operated valves have been provided, possessing to at least a reasonable degree, some of the operating characteristics similar to those briefly described.
One such valve type incorporates a spherical ball shaped core as a method of control, and according to rotational axial positioning, of the core, within the valve body, flow is initiated or terminated. Most often, an advantage in the utilization of this valve type is the ability to control rapid initialization, or termination, of full flow through the valve, however, considerable control difficulty is usually encountered in obtaining an exact, precise, metered adjustment, of the rate of flow passing through the valve, which may be necessary on some applications.
And another such valve type utilizes a needle core as a method of control, and according to adjustment of the core, readily provides exact, precise, metered control of the rate of flow passing through the valve. This valve type, conversely, is usually much slower to initiate or terminate flow through the valve, making it undesirable for use on applications that require rapid initialization or termination of flow.
And still another such valve type utilizes a tapered core for the primary control of flow and a needle member residing within the tapered core for secondary control of flow. The valve is one among several other members of a larger device and is specifically designed and intended to support the rather unique operating characteristics inherent to the overall operation of the larger device. Were if separated therefrom, the valve could not be readily utilized in a common manner to provide control of a pressure flow due to either its distinct structural design, or its dependance upon other members being a part of the larger device, or the unique operating conditions inherent of the larger device.
And still yet another such valve type similarly utilizes a tapered core for its primary Flow control having a needle residing within the core providing secondary control of flow. The primary control of flow through the valve, as provided by the tapered core, is accessible and readily operable, however, the secondary control of flow is normally inaccessible suggesting that once it is positioned it is intended to remain as positioned for an extended period of time, so as the initiation of flow is commonly usually controlled by the sole positioning of the tapered core and the more precise metering of flow is not commonly reset.